TY - JOUR
T1 - Fast ion losses due to toroidal field ripple in JT-60U
AU - Tobita, K.
AU - Tani, K.
AU - Nishitani, T.
AU - Nagashima, K.
AU - Kusama, Y.
PY - 1994
Y1 - 1994
N2 - A previous experiment in JT-60U supported an orbit following Monte Carlo (OFMC) calculation regarding ripple trapped loss, and the present experiment, furthermore, suggests that the OFMC also predicts banana drift loss fairly well. In the experiment presented, the total fast ion losses due to toroidal field ripple were estimated from the decay in neutron emission following a short neutral beam injection (90 keV, D). The neutron decay for co-passing beam injection showed a diffusivity of about 0 m2/s, which indicates no fast ion loss. In contrast, the neutron decay for trapped particle injection exhibited characteristic enhancement of fast ion losses due to toroidal field ripple: the fast ion losses consisted of ripple trapped convection and ripple banana diffusion in the low collisionality regime. The OFMC calculation reconstructed completely the experimental neutron decay irrespective of the total ripple losses and the fraction of banana drift loss. Considering the previous work on ripple trapped loss and this result, it can be concluded that the OFMC code gives a good quantitative estimation of banana drift loss as well as ripple trapped loss.
AB - A previous experiment in JT-60U supported an orbit following Monte Carlo (OFMC) calculation regarding ripple trapped loss, and the present experiment, furthermore, suggests that the OFMC also predicts banana drift loss fairly well. In the experiment presented, the total fast ion losses due to toroidal field ripple were estimated from the decay in neutron emission following a short neutral beam injection (90 keV, D). The neutron decay for co-passing beam injection showed a diffusivity of about 0 m2/s, which indicates no fast ion loss. In contrast, the neutron decay for trapped particle injection exhibited characteristic enhancement of fast ion losses due to toroidal field ripple: the fast ion losses consisted of ripple trapped convection and ripple banana diffusion in the low collisionality regime. The OFMC calculation reconstructed completely the experimental neutron decay irrespective of the total ripple losses and the fraction of banana drift loss. Considering the previous work on ripple trapped loss and this result, it can be concluded that the OFMC code gives a good quantitative estimation of banana drift loss as well as ripple trapped loss.
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U2 - 10.1088/0029-5515/34/8/I04
DO - 10.1088/0029-5515/34/8/I04
M3 - Article
AN - SCOPUS:0343276247
SN - 0029-5515
VL - 34
SP - 1097
EP - 1109
JO - Nuclear Fusion
JF - Nuclear Fusion
IS - 8
M1 - I04
ER -